Photomultiplication type full-flexible lead-free perovskite photosensitive diode and preparation method thereof

Abstract

The invention discloses a photomultiplication type full-flexible lead-free perovskite photosensitive diode and a preparation method thereof, and the device comprises a flexible substrate 1, an organic flexible electrode anode 2, an organic flexible hole transport layer 3, a lead-free perovskite photosensitive layer 4, an organic flexible electron transport layer 5, an organic flexible electrode cathode 7 and a packaging layer 8. Wherein the flexible substrate 1, the organic flexible electrode anode 2, the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7 are sequentially stacked from bottom to top. The flexible substrate and the functional layers compatible with the flexible substrate are adopted, so that the photomultiplier has good mechanical flexibility, meanwhile, the lead-free perovskite with high photoelectric conversion efficiency is adopted, the device is environmentally friendly, and the detector is suitable for weak light detection by adopting a multiplication strategy.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor optoelectronic devices, and in particular relates to a photomultiplier-type fully flexible lead-free perovskite photodiode and a preparation method thereof. Background Art

[0002] As core components of modern optoelectronics, photodetectors play an irreplaceable role in imaging monitoring, optical communications, biosensing, national defense, and security. While traditional silicon-based detectors and vacuum photomultiplier tubes (PMTs) are mature technologies, their inherent rigidity severely restricts their application in flexible electronics. The brittle nature of silicon makes them difficult to adapt to emerging applications such as wearable devices and curved detectors. While PMTs offer excellent gain performance, they are limited by their bulk, high power consumption, and the inability to flexibly integrate them. Furthermore, conventional lead-containing perovskites pose a certain degree of environmental pollution and toxicity. Therefore, the development of flexible, stable, and environmentally friendly PMTs is an urgent challenge. Summary of the Invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a photomultiplier-type fully flexible lead-free perovskite photodiode and a preparation method thereof. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0004] A photomultiplier-type fully flexible lead-free perovskite photodiode, comprising a flexible substrate 1, an organic flexible electrode anode 2, an organic flexible hole transport layer 3, a lead-free perovskite photosensitive layer 4, an organic flexible electron transport layer 5, an organic flexible electrode cathode 7 and an encapsulation layer 8, wherein:

[0005] The flexible substrate 1, the organic flexible electrode anode 2, the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7 are stacked in sequence from bottom to top;

[0006] The encapsulation layer 8 is located on the upper surface of the organic flexible electrode cathode 7 and the upper surface of the organic flexible electrode anode 2, and is located on the side surfaces of the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7;

[0007] The organic flexible electrode cathode 7 completely covers the organic flexible electron transport layer 5 in the form of a thin film, or is evenly distributed on the surface of the organic flexible electron transport layer 5 in the form of a carbon nanotube array.

[0008] In a specific embodiment, the flexible substrate 1 is any one of polyethylene terephthalate, polyethylene naphthalate, fluorinated polyimide, and polydimethylsiloxane; the organic flexible electrode anode 2 and the organic flexible electrode cathode 7 are any one of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate), polyaniline, and polypyrrole.

[0009] In a specific embodiment, the lead-free perovskite photosensitive layer 4 is any one of ABX3 germanium-based perovskite, bismuth-based perovskite, and tin-based perovskite, wherein A is an organic cation, B is an inorganic metal cation, and X is a halogen ion.

[0010] In a specific embodiment, the organic flexible hole transport layer 3 is any one of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate), poly(3-hexylthiophene), poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine], 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene, and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]; the organic flexible electron transport layer 5 is any one of [6,6]-phenyl-C71-butyric acid methyl ester, poly(9,9-dioctylfluorene-alternate-benzo[2,1,3]thiophene), polyetherimide, fullerene, and 8-hydroxyquinoline aluminum; wherein,

[0011] The doping material of the organic flexible electron transport layer 5 is any one of molybdenum oxide, 4,4′-bis(diphenylamino)cyclohexane, and poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alternating-2,7-(9,9-dioctylfluorene)].

[0012] In a specific embodiment, the thickness of the flexible substrate 1 is 50-500 μm, the thickness of the organic flexible electrode anode 2 is about 50-100 nm, the thickness of the organic flexible hole transport layer 3 is 30-300 nm, the thickness of the lead-free perovskite photosensitive layer 4 is 100-1000 nm, the thickness of the organic flexible electron transport layer 5 is 20-200 nm, and the thickness of the organic flexible electrode cathode 7 is 50-100 nm.

[0013] In a specific embodiment, an interface barrier layer 6 is further included, which is located between the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7 .

[0014] In a specific embodiment, the interface barrier layer 6 is any one of 4,4′-bis(diphenylamino)cyclohexane, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2′,7,7′-tetra[N-(1-naphthyl)-phenyl]-9,9′-spirobifluorene, and 1,4-poly(p-phenyl).

[0015] In a specific embodiment, the thickness of the interface barrier layer 6 is 5-20 nm.

[0016] The present invention also provides a method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode, comprising:

[0017] S1: Select flexible substrate 1 and perform pre-treatment;

[0018] S2: growing an organic flexible electrode anode 2 on the surface of the pre-treated flexible substrate 1;

[0019] S3: growing an organic flexible hole transport layer 3 on the surface of the organic flexible electrode 2;

[0020] S4: growing a lead-free perovskite photosensitive layer 4 on the surface of the organic flexible hole transport layer 3;

[0021] S5: growing an organic flexible electron transport layer 5 on the surface of the lead-free perovskite photosensitive layer 4;

[0022] S6: growing an organic flexible electrode cathode 7 on the surface of the organic flexible electron transport layer 5;

[0023] S7: A layer of transparent medium is grown as an encapsulation layer 8 on the upper surface of the organic flexible electrode anode 2 and the organic flexible electrode cathode 7, and on the sides of the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7, to finally form the photomultiplier type fully flexible lead-free perovskite photosensitive diode.

[0024] In a specific embodiment, between S5 and S6 , an interface barrier layer 6 is further grown on the surface of the organic flexible electron transport layer 5 .

[0025] Beneficial effects of the present invention:

[0026] 1. The present invention utilizes a flexible substrate and various functional layers compatible with the flexible substrate, which not only imparts excellent mechanical flexibility to the photomultiplier tube, but also offers low cost, ease of fabrication, and scalable production for large-scale applications. It can be used in a new generation of flexible, wearable optoelectronic products. The use of a high-mobility organic semiconductor as a hole transport layer, a high-photoelectric conversion efficiency, lead-free, environmentally friendly perovskite material, and an organic film capable of ion migration within the film as a flexible photomultiplier layer enables the device to exhibit typical photomultiplication characteristics, achieving optical signal amplification, high sensitivity, and excellent performance, including high photocurrent, high responsivity, high external quantum efficiency (EQE), and high gain. This device represents a highly promising multifunctional, high-performance optoelectronic application unit for the next generation of optoelectronic products.

[0027] 2. The device prepared by the method of the present invention uses a high-mobility organic semiconductor material as a carrier transport layer, which accelerates the transmission of carriers from the active layer to the electrode and reduces the loss of charge during the transmission process. At the same time, it solves the problem of slow response speed of the multiplier tube to a certain extent, effectively adjusts the energy level matching in the device, and reduces the resistance and energy loss at the interface. This not only improves the charge collection efficiency, but also makes the device compatible and flexible, and has certain potential in the wearable field.

[0028] 3. In view of the toxicity of lead-based perovskites, the present invention adopts non-lead-based perovskites to avoid the pollution of the detector to the environment and harm to the human body. At the same time, the perovskite film is composed of grains, and the perovskite photosensitive layer inevitably contains the problem of vertical shunt paths. Compared with lead-based perovskites, the present invention adopts tin-based perovskites or germanium-based perovskites to introduce divergent paths by appropriately reducing the perovskite grain size, thereby reducing the defect of large dark current caused by vertical shunt.

[0029] 4. The perovskite used in the photosensitive layer material of the present invention does not need to be made into a heterojunction, thereby avoiding the impact on the light absorption properties of the perovskite. In addition, in the design of the multiplication mechanism, the present invention achieves efficient carrier gain through the following control strategies: selecting an electron transport layer material with a low lowest unoccupied molecular orbital (LUMO) energy level (i.e., deep energy level) to accumulate electrons in the electron transport layer, thereby inducing electron transport layer band bending; or selecting an electron transport layer material with a higher LUMO energy level to accumulate electrons at the perovskite / electron transport layer (ETL) interface, thereby inducing electron transport layer band bending; or introducing a high-barrier interface blocking layer to induce dense electron aggregation and local band bending effects.

[0030] 5. The present invention is a photomultiplier tube type light detector. Compared with the previous photomultiplier tube type light detector, the present invention has the advantages of flexibility, high EQE, relatively high response speed, environmental friendliness and stability in the environment.

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0033] Figure 2 This is a schematic structural diagram of another photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the low LUMO energy level induced multiplication energy level structure of the electron transport layer of a photomultiplier type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the high LUMO energy level induced multiplication energy level structure of the electron transport layer of a photomultiplier type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of the electrical interface barrier layer induced multiplication energy level of a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0037] Figure 6 This is a flow chart of a method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0038] Figure 7 This is a flow chart of another method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention;

[0039] Figures 8a to 8g A flow chart of a method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode provided in an embodiment of the present invention;

[0040] Figure 9a to Figure 9h A flow chart of a method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0042] Example 1

[0043] See Figure 1 , Figure 1 Schematic diagram of the structure of a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention, comprising:

[0044] Flexible substrate 1, organic flexible electrode anode 2, organic flexible hole transport layer 3, lead-free perovskite photosensitive layer 4, organic flexible electron transport layer 5, organic flexible electrode cathode 7 and encapsulation layer 8, wherein:

[0045] The flexible substrate 1, the organic flexible electrode anode 2, the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7 are stacked in sequence from bottom to top;

[0046] The encapsulation layer 8 is located on the upper surface of the organic flexible electrode cathode 7 and the upper surface of the organic flexible electrode anode 2, and is located on the side surfaces of the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7;

[0047] The organic flexible electrode cathode 7 completely covers the organic flexible electron transport layer 5 in the form of a thin film, or is evenly distributed on the surface of the organic flexible electron transport layer 5 in the form of a carbon nanotube array.

[0048] In a specific embodiment of the present invention, the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7 are sequentially located in the middle of the upper surface of the organic flexible electrode anode 2.

[0049] In a specific embodiment of the present invention, the flexible substrate 1 is any one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), fluorinated polyimide (PI), and polydimethylsiloxane (PDMS).

[0050] In a specific embodiment of the present invention, the organic flexible electrode anode 2 and the organic flexible electrode cathode 7 are any one of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS), polyaniline (PANI), and polypyrrole (PPy).

[0051] Preferably, the model of PEDOT:PSS may be PH1000.

[0052] In a specific embodiment of the present invention, the material of the lead-free perovskite photosensitive layer 4 is any one of germanium-based perovskite, bismuth-based perovskite, and tin-based perovskite with a structure of ABX3, wherein A represents an organic cation, which can be CH3NH3 + or HC(NH2)2 + , B represents an inorganic metal cation, which can be Ge 2+ 、Sn 2+ Or Ge2+ 0.5 Sn 2+ 0.5 , X represents a halogen ion, which can be I - Br - or Cl - ; The specific materials can be methyl ether tin iodide (FASnI3 (FA=CH(NH2)2)), methylamine tin iodide (CH3NH3SnI3), methylamine tin germanium iodide ((CH3NH3)2SnGeI6), etc.

[0053] In a specific embodiment of the present invention, the organic flexible hole transport layer 3 is any one of PEDOT:PSS, poly (3-hexylthiophene) (P3HT), poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) - benzidine] (Poly-TPD), 2,2',7,7'-tetrakis [N, N-bis (4-methoxyphenyl) amino] -9,9'-spirobifluorene (Spiro-OMeTAD), and poly [bis (4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA); the material of the organic flexible electron transport layer 5 is [6,6] -phenyl -C71-butyric acid methyl ester (PC 71 BM), poly (9,9-dioctylfluorene-alt-benzo [2,1,3] thiophene) (F8BT), polyetherimide (PEIE), fullerene (C 60 ), any one of 8-hydroxyquinoline aluminum (Alq3), the organic flexible electron transport layer 5 needs to be doped, and the optional doping material is any one of molybdenum oxide (MoO3), 4,4′-bis(diphenylamino)cyclohexane (TAPC), and poly[(9,9-bis(3′(N,N-dimethylamino)propyl)-2,7-fluorene)-alternating-2,7-(9,9-dioctylfluorene)](PFN).

[0054] It can be understood that the present invention achieves efficient carrier gain through a control strategy: an electron transport layer material with a low LUMO energy level (i.e., a deep energy level) can be selected to accumulate electrons at the electron transport layer, thereby inducing electron transport layer band bending; an electron transport layer material with a higher LUMO energy level can also be selected to accumulate electrons at the perovskite / ETL interface, thereby inducing electron transport layer band bending; or a high-barrier interface blocking layer can be introduced to induce dense electron aggregation and localized band bending effects.

[0055] Specifically, if Figure 3 As shown, Figure 3This is a schematic diagram of the low LUMO energy level induced multiplication energy level structure of the electron transport layer of a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention. The low LUMO energy level is obtained by using an electron transport layer with a low LUMO energy level or by regulating the electron transport layer through doping. Under dark conditions, due to the high LUMO energy level of the hole transport layer (HTL) and the low highest occupied molecular orbital (HOMO) energy level of the ETL, high energy barriers are formed between the anode and HTL, and between the cathode and ETL. Electrons cannot be injected into the device from the anode, and holes cannot be injected into the device from the cathode. At this time, the device has an extremely low dark current. Under illumination, the perovskite absorbs light to generate photogenerated carriers. Under reverse bias, electrons drift from the perovskite to the ETL. At this time, due to the low LUMO energy level of the ETL, electrons will accumulate in the ETL, resulting in band bending at the ETL / cathode interface, making the hole barrier width at the ETL / cathode interface thinner. Holes in the external circuit can be injected into the device through tunneling from the cathode, and transmitted along the device to the anode side, and finally collected by the anode to form a multiplied current.

[0056] Specifically, if Figure 4 As shown, Figure 4 This is a schematic diagram of the high LUMO energy level-induced multiplication energy level structure of the electron transport layer of a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention; a high LUMO energy level is obtained by using an electron transport layer with a high LUMO energy level or by regulating the electron transport layer through doping. Under dark conditions, due to the high LUMO energy level of the HTL and the low HOMO energy level of the ETL, high energy barriers are formed between the anode and the HTL, and between the cathode and the ETL. Electrons cannot enter the device from the anode, and holes cannot enter the device from the cathode. At this time, the device has an extremely low dark current. Under illumination, the perovskite absorbs light to generate photogenerated carriers. Under reverse bias, due to the blocking effect of the LUMO energy level barrier of the ETL, electrons will accumulate at the perovskite / ETL interface. When the ETL layer thickness is relatively thin, it will cause a strong bending of the ETL layer energy band, thereby thinning the hole injection barrier width at the cathode / ETL interface. Holes in the external circuit can tunnel from the cathode to the device and transmit along the device to the anode side. Finally, they are collected by the anode to form a multiplied current.

[0057] The material selection of the specific embodiment of the present invention satisfies the multiplication principle Figure 3 or Figure 4 The band structure shown.

[0058] In a specific embodiment of the present invention, the thickness of the flexible substrate 1 is 50-500 μm, the thickness of the organic flexible electrode anode 2 is about 50-100 nm, the thickness of the organic flexible hole transport layer 3 is 30-300 nm, the thickness of the lead-free perovskite photosensitive layer 4 is 100-1000 nm, the thickness of the organic flexible electron transport layer 5 is 20-200 nm, and the thickness of the organic flexible electrode cathode 7 is 50-100 nm.

[0059] See Figure 6 , Figure 6 This is a flow chart of a method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention, comprising:

[0060] S1: Select flexible substrate 1 and perform pre-treatment, such as Figure 8a As shown;

[0061] In a specific embodiment of the present invention, the flexible substrate 1 is made of any one of PET, PEN, PI or PDMS, and the pretreatment includes scrubbing the flexible substrate 1 with a detergent, then ultrasonically cleaning the flexible substrate 1 in acetone, ethanol, and deionized water for ten minutes respectively, placing it on a hot plate to remove residual moisture and solvent, and then treating it with UV-ozone for 20 minutes.

[0062] S2: growing an organic flexible electrode anode 2 on the surface of the pre-treated flexible substrate 1, such as Figure 8b As shown;

[0063] In a specific embodiment of the present invention, the organic flexible electrode anode 2 is any one of PEDOT:PSS, PANI, and PPy thin films.

[0064] Preferably, the model of PEDOT:PSS may be PH1000.

[0065] As a preferred embodiment, taking PANI as an example, polyaniline powder is dissolved in an appropriate amount of N-methylpyrrolidone (NMP) solution, and magnetic stirring is performed until it is completely dissolved to obtain a precursor solution of the organic flexible electrode anode 2. The precursor solution is evenly coated on the flexible substrate 1, first spin-coated at a low speed of 500-1000 rpm for 5-10 seconds, then spin-coated at 2500 rpm for 30 seconds, and finally annealed at 60°C-80°C for 20 minutes to prepare the organic flexible electrode anode 2.

[0066] S3: growing an organic flexible hole transport layer 3 on the surface of the organic flexible electrode 2, such as Figure 8c As shown;

[0067] In a specific embodiment of the present invention, the organic flexible hole transport layer 3 is any one of PEDOT:PSS, Poly-TPD, P3HT, Spiro-OMeTAD, and PTAA, and the specific growth method is to spin-coat on the organic flexible electrode anode 2 at a certain speed, spin-coat for a certain time, and then heat and dry for a certain time in a glove box filled with high-purity nitrogen (N2).

[0068] As a preferred embodiment, the organic flexible hole transport layer PEDOT:PSS is used as an example to illustrate that the PEDOT:PSS solution is heated at 5000 rpm and an acceleration of 1000 rpm s -1 The organic flexible hole transport layer 3 was prepared by spin coating on the organic flexible electrode anode 2 for 30 seconds and drying at 150° C. for 15 minutes in a glove box filled with high-purity N 2 .

[0069] S4: growing a lead-free perovskite photosensitive layer 4 on the surface of the organic flexible hole transport layer 3, such as Figure 8d As shown;

[0070] In a specific embodiment of the present invention, the method for preparing the lead-free perovskite photosensitive layer can be a solution spin coating method or a vacuum evaporation method.

[0071] Among them, the solution spin coating method includes operations such as preparing a precursor solution, spin coating film formation, and annealing.

[0072] As a preferred embodiment, taking the growth of FASnI3 film as an example, in an environment without water and oxygen and filled with high-purity N2, FAI and SnI2 are mixed in a molar ratio of 1:1 and dissolved in a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (volume ratio of 4:1), and magnetically stirred at 50°C for 8 hours to prepare a perovskite precursor solution; then, the mixture is heated at 1000 rpm and an acceleration of 500 rpm s -1 The precursor solution was spin-coated on the organic flexible hole transport layer 3 for 10 seconds, and then the spin-coated solution was spin-coated at 5000 rpm with an acceleration of 1000 rpm s -1 The process was spin-coated for 45 seconds, and 400 μL of anti-solvent acetonitrile (ACN) was added dropwise after 25 seconds. Finally, the process was thermally annealed at 70° C. for 10 minutes in a glove box filled with N 2 to prepare the lead-free perovskite photosensitive layer 4 .

[0073] Among them, the vacuum evaporation method includes placing two precursors of the required perovskite (such as phenylethylammonium tin iodide, the precursors are phenylethylammonium iodide and tin iodide) into a vacuum coating machine, controlling the power so that the evaporation rate of the two materials remains at a rate of 1:3, and depositing them on the organic flexible hole transport layer 3. The reaction generates the required perovskite film to prepare the lead-free perovskite photosensitive layer 4.

[0074] S5: growing an organic flexible electron transport layer 5 on the surface of the lead-free perovskite photosensitive layer 4, such as Figure 8e As shown;

[0075] In a specific embodiment of the present invention, the organic flexible electron transport layer 5 can be prepared by a spin coating method.

[0076] As a preferred embodiment, PC 71 Take BM as an example, PC 71 BM was dissolved in chlorobenzene (CB), and the solution was stirred for 2 hours, ultrasonicated for 2 hours, and then stirred for 1 hour to prepare an organic flexible electron transport layer precursor solution. The precursor solution was dropped onto the lead-free perovskite photosensitive layer 4 in a glove box filled with N2 at a speed of 5000 rpm and an acceleration of 1000 rpm s -1 The organic flexible electron transport layer 5 was prepared by spin coating for 30 seconds, annealing at 60° C. for 1 minute, and then annealing at 100° C. for 10 minutes.

[0077] S6: growing an organic flexible electrode cathode 7 on the surface of the organic flexible electron transport layer 5, such as Figure 8f As shown;

[0078] In a specific embodiment of the present invention, the organic flexible electrode cathode 7 is any one of PEDOT:PSS, PANI, and PPy films.

[0079] Preferably, the model of PEDOT:PSS may be PH1000.

[0080] As a preferred embodiment, taking PANI as an example, polyaniline powder is dissolved in an appropriate amount of N-methylpyrrolidone (NMP) solution, and magnetically stirred until completely dissolved to obtain a precursor solution of the organic flexible electrode cathode 7. The precursor solution is evenly coated on the organic flexible electron transport layer 5, first spin-coated at a low speed of 500-1000 rpm for 5-10 seconds, then spin-coated at 2500 rpm for 30 seconds, and finally annealed at 60°C-80°C for 20 minutes to prepare the organic flexible electrode cathode 7.

[0081] In a specific embodiment of the present invention, if the organic flexible electrode cathode 7 is a carbon nanotube, the growth method is to synthesize it by injection chemical vapor deposition (FCCVD). Specifically, N2 is used as a carrier gas, and a liquid carbon source (for example, toluene), a catalyst precursor (for example, ferrocene) and a growth promoter (for example, thiophene) are mixed in a weight ratio of 10:0.3:0.045. Then, the mixture is injected into a quartz tube reactor at a rate of 0.33 mL / h through an injection pump to grow carbon nanotubes. A membrane filter with a pore size of 0.45 μm is connected to the gas outlet, and the grown carbon nanotubes are collected at room temperature and transferred to the upper surface of the organic flexible electron transport layer 5 to prepare the organic flexible electrode cathode 7.

[0082] S7: A layer of transparent medium is grown as an encapsulation layer 8 on the upper surface of the organic flexible electrode anode 2 and the organic flexible electrode cathode 7, and on the side of the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5 and the organic flexible electrode cathode 7, to finally form the photomultiplier type fully flexible lead-free perovskite photosensitive diode, such as Figure 8g shown.

[0083] In a specific embodiment of the present invention, a polymethyl methacrylate (PMMA) or cyclic transparent optical polymer (CYTOP) silicone resin transparent encapsulation layer can be prepared by vacuum evaporation or solution spin coating.

[0084] The embodiments of the present invention utilize a flexible substrate and various functional layers compatible with the flexible substrate. Except for the photosensitive layer, all other layers utilize organic materials. This not only imparts good mechanical flexibility to the photomultiplier tube, but also is low-cost, easy to prepare, and capable of large-scale production. It is expected to be used in a new generation of flexible, wearable optoelectronic products. The high-mobility organic semiconductor material employed as the hole transport layer accelerates the transport of holes from the active layer to the electrode, while also addressing, to a certain extent, the slow response speed of the photomultiplier tube. The specifically designed and effectively adjusted energy level arrangement within the device reduces issues such as resistance and energy loss at the interface. The environmentally friendly lead-free perovskite employed also introduces a divergent path, mitigating the large dark current drawbacks caused by vertical shunting. This is a highly flexible and sensitive optoelectronic application unit with great potential in a new generation of optoelectronic products.

[0085] Example 2

[0086] See Figure 2 , Figure 2 This is a schematic structural diagram of another photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention, comprising:

[0087] Flexible substrate 1, organic flexible electrode anode 2, organic flexible hole transport layer 3, lead-free perovskite photosensitive layer 4, organic flexible electron transport layer 5, interface barrier layer 6, organic flexible electrode cathode 7 and encapsulation layer 8, wherein:

[0088] The flexible substrate 1, the organic flexible electrode anode 2, the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5, the interface barrier layer 6 and the organic flexible electrode cathode 7 are stacked in sequence from bottom to top;

[0089] The encapsulation layer 8 is located on the upper surface of the organic flexible electrode cathode 7 and the upper surface of the organic flexible electrode anode 2, and is located on the side surfaces of the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5, the interface barrier layer 6 and the organic flexible electrode cathode 7;

[0090] The organic flexible electrode cathode 7 completely covers the interface barrier layer 6 in the form of a thin film, or is evenly distributed on the upper surface of the interface barrier layer 6 in the form of a carbon nanotube array.

[0091] In a specific embodiment of the present invention, the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5, the interface blocking layer 6 and the organic flexible electrode cathode 7 are located in the middle of the upper surface of the organic flexible electrode anode 2.

[0092] In a specific embodiment of the present invention, the flexible substrate 1 is any one of PET, PEN, PI, and PDMS.

[0093] In a specific embodiment of the present invention, the organic flexible electrode anode 2 and the organic flexible electrode cathode 7 are any one of PEDOT:PSS, PANI, and PPy.

[0094] Preferably, the model of PEDOT:PSS may be PH1000.

[0095] In a specific embodiment of the present invention, the material of the lead-free perovskite photosensitive layer 4 is any one of germanium-based perovskite, bismuth-based perovskite, and tin-based perovskite with a structure of ABX3, wherein A represents an organic cation, which can be CH3NH3 + or HC(NH2)2 + , B represents an inorganic metal cation, which can be Ge 2+ 、Sn 2+ Or Ge 2+ 0.5 Sn 2+ 0.5 , X represents a halogen ion, which can be I - Br- or Cl - ; The specific materials can be FASnI3, CH3NH3SnI3, (CH3NH3)2SnGeI6, etc.

[0096] In a specific embodiment of the present invention, the organic flexible hole transport layer 3 is any one of PEDOT:PSS, P3HT, Poly-TPD, Spiro-OMeTAD, and PTAA; the material of the organic flexible electron transport layer 5 is PC 71 BM, F8BT, PEIE, C 60 , Alq3, the organic flexible electron transport layer 5 needs to be doped, and the optional doping material is any one of MoO3, TAPC, and PFN.

[0097] In a specific embodiment of the present invention, the interface barrier layer 6 is any one of TAPC, PTAA, 2,2',7,7'-tetrakis[N-(1-naphthyl)-phenyl]-9,9'-spirobifluorene (BCP), and 1,4-poly(p-phenyl) (PPP).

[0098] Specifically, if Figure 5 As shown, Figure 5 This is a schematic diagram of the structure of the electrical interface barrier induced multiplication energy level of a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention; an interface barrier layer with a high LUMO energy level is used. Under dark conditions, due to the high LUMO energy level of the HTL and the low HOMO energy level of the ETL, high energy barriers are formed between the anode and the HTL, and between the cathode and the ETL. Electrons cannot enter the device from the anode, and holes cannot enter the device from the cathode. At this time, the device has an extremely low dark current. Under illumination, the perovskite absorbs light to generate photogenerated carriers. Under reverse bias, due to the blocking effect of the high LUMO energy level barrier of the interface barrier layer, electrons will accumulate in the ETL, causing the energy band of the ETL / cathode interface to be sharply bent, thereby thinning the barrier width of the cathode / ETL interface. Holes in the external circuit can be injected into the device from the cathode through tunneling, and are transmitted along the device to the anode side, and are finally collected by the anode to form a multiplied current.

[0099] The material selection of the specific embodiment of the present invention satisfies the multiplication principle Figure 5 The band structure shown.

[0100] In a specific embodiment of the present invention, the thickness of the flexible substrate 1 is 50-500 μm, the thickness of the organic flexible electrode anode 2 is about 50-100 nm, the thickness of the organic flexible hole transport layer 3 is 30-300 nm, the thickness of the lead-free perovskite photosensitive layer 4 is 100-1000 nm, the thickness of the organic flexible electron transport layer 5 is 20-200 nm, and the thickness of the organic flexible electrode cathode 7 is 50-100 nm.

[0101] In a specific embodiment of the present invention, the thickness of the interface barrier layer 6 is 5-20 nm.

[0102] See Figure 7 , Figure 7 This is a flow chart of another method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode provided by an embodiment of the present invention, comprising:

[0103] S1: Select flexible substrate 1 and perform pre-treatment, such as Figure 9a As shown;

[0104] In a specific embodiment of the present invention, the flexible substrate 1 is taken from any one of PET, PEN, PI, and PDMS. The pretreatment includes scrubbing the flexible substrate 1 with a detergent, then ultrasonically cleaning the flexible substrate 1 in acetone, ethanol, and deionized water for ten minutes respectively, placing it on a hot plate to remove residual moisture and solvent, and then treating it with UV-ozone for 20 minutes.

[0105] S2: growing an organic flexible electrode anode 2 on the surface of the flexible substrate 1 after pretreatment, such as Figure 9b As shown;

[0106] In a specific embodiment of the present invention, the organic flexible electrode anode 2 is any one of PEDOT:PSS, PANI, and PPy thin films.

[0107] Preferably, the model of PEDOT:PSS may be PH1000.

[0108] As a preferred embodiment, taking PANI as an example, polyaniline powder is dissolved in an appropriate amount of NMP solution, and magnetic stirring is performed until it is completely dissolved to obtain a precursor solution of the organic flexible electrode anode 2. The precursor solution is evenly coated on the flexible substrate 1, first spin-coated at a low speed of 500-1000 rpm for 5-10 seconds, then spin-coated at 2500 rpm for 30 seconds, and finally annealed at 60°C-80°C for 20 minutes to prepare the organic flexible electrode anode 2.

[0109] S3: growing an organic flexible hole transport layer 3 on the surface of the organic flexible electrode 2, such as Figure 9c As shown;

[0110] In a specific embodiment of the present invention, the organic flexible hole transport layer 3 is any one of PEDOT:PSS, Poly-TPD, P3HT, Spiro-OMeTAD, and PTAA, and the specific growth method is to spin-coat on the organic flexible electrode anode 2 at a certain speed, spin-coat for a certain time, and then heat and dry for a certain time in a glove box filled with high-purity N2.

[0111] As a preferred embodiment, the organic flexible hole transport layer PEDOT:PSS is used as an example to illustrate that the PEDOT:PSS solution is heated at 5000 rpm and an acceleration of 1000 rpm s -1 The organic flexible hole transport layer 3 was prepared by spin coating on the organic flexible electrode anode 2 for 30 seconds and drying at 150° C. for 15 minutes in a glove box filled with high-purity N 2 .

[0112] S4: growing a lead-free perovskite photosensitive layer 4 on the surface of the organic flexible hole transport layer 3, such as Figure 9d As shown;

[0113] In a specific embodiment of the present invention, the method for preparing the lead-free perovskite photosensitive layer can be a solution spin coating method or a vacuum evaporation method.

[0114] Among them, the solution spin coating method includes operations such as preparing a precursor solution, spin coating film formation, and annealing.

[0115] As a preferred embodiment, taking the growth of FASnI3 film as an example, in an environment without water and oxygen and filled with high-purity N2, FAI and SnI2 are mixed in a molar ratio of 1:1 and dissolved in a mixed solution of DMF and DMSO (volume ratio 4:1), and magnetically stirred at 50°C for 8 hours to prepare a perovskite precursor solution; then, the mixture is heated at 1000 rpm and an acceleration of 500 rpm s -1 The precursor solution was spin-coated on the organic flexible hole transport layer 3 for 10 seconds, and then the spin-coated solution was spin-coated at 5000 rpm and an acceleration of 1000 rpms. -1 The process was spin-coated for 45 seconds, and 400 μL of anti-solvent ACN was added dropwise after 25 seconds. Finally, the process was thermally annealed at 70° C. for 10 minutes in a glove box filled with N 2 to prepare the lead-free perovskite photosensitive layer 4 .

[0116] Among them, the vacuum evaporation method includes placing two precursors of the required perovskite (such as phenylethylammonium tin iodide, the precursors are phenylethylammonium iodide and tin iodide) into a vacuum coating machine, controlling the power so that the evaporation rate of the two materials remains at a rate of 1:3, and depositing them on the organic flexible hole transport layer 3. The reaction generates the required perovskite film to prepare the lead-free perovskite photosensitive layer 4.

[0117] S5: growing an organic flexible electron transport layer 5 on the surface of the lead-free perovskite photosensitive layer 4, such as Figure 9e As shown;

[0118] In a specific embodiment of the present invention, the organic flexible electron transport layer 5 can be prepared by a spin coating method.

[0119] As a preferred embodiment, PC 71 Take BM as an example, PC 71 BM was dissolved in CB, and the solution was stirred for 2 hours, ultrasonically treated for 2 hours, and then stirred for 1 hour to prepare an organic flexible electron transport layer precursor solution. The precursor solution was dropped onto the lead-free perovskite photosensitive layer 4 in a glove box filled with N2 at a speed of 5000 rpm and an acceleration of 1000 rpm s -1 The organic flexible electron transport layer 5 was prepared by spin coating for 30 seconds, annealing at 60° C. for 1 minute, and then annealing at 100° C. for 10 minutes.

[0120] S6: growing an interface barrier layer 6 on the surface of the organic flexible electron transport layer 5, such as Figure 9f As shown;

[0121] In a specific embodiment of the present invention, the interface barrier layer 6 is any one of TAPC, PTAA, BCP, and PPP.

[0122] As a preferred embodiment, taking BCP as an example, the BCP precursor solution dissolved in isopropyl alcohol is evenly spread on the organic flexible electron transport layer 5, and the speed is 1500 rpm, 500 rpm s -1 The interface barrier layer 6 was prepared by spin coating at an acceleration of 40 seconds and annealing at 100° C. for 30 minutes in a glove box filled with N 2 .

[0123] S7: growing an organic flexible electrode cathode 7 on the surface of the interface barrier layer 6, such as Figure 9g As shown;

[0124] In a specific embodiment of the present invention, the organic flexible electrode cathode 7 is any one of PEDOT:PSS, PANI, and PPy films.

[0125] Preferably, the model of PEDOT:PSS may be PH1000.

[0126] As a preferred embodiment, taking PANI as an example, polyaniline powder is dissolved in an appropriate amount of NMP solution, and magnetic stirring is performed until it is completely dissolved to obtain a precursor solution of the organic flexible electrode cathode 7. The precursor solution is evenly coated on the interface barrier layer 6, first spin-coated at a low speed of 500-1000 rpm for 5-10 seconds, then spin-coated at 2500 rpm for 30 seconds, and finally annealed at 60°C-80°C for 20 minutes to prepare the organic flexible electrode cathode 7.

[0127] In a specific embodiment of the present invention, if the organic flexible electrode cathode 7 is a carbon nanotube, the growth method is to synthesize it by the FCCVD method. Specifically, using N2 as a carrier gas, a liquid carbon source (for example, toluene), a catalyst precursor (for example, ferrocene) and a growth promoter (for example, thiophene) are mixed in a weight ratio of 10:0.3:0.045, and then the mixture is injected into a quartz tube reactor at a rate of 0.33 mL / h through an injection pump to grow carbon nanotubes. A membrane filter with a pore size of 0.45 μm is connected to the gas outlet, and the grown carbon nanotubes are collected at room temperature and transferred to the upper surface of the interface barrier layer 6 to prepare the organic flexible electrode cathode 7.

[0128] S8: growing a layer of transparent medium as an encapsulation layer 8 on the upper surface of the organic flexible electrode anode 2 and the organic flexible electrode cathode 7, and on the side of the organic flexible hole transport layer 3, the lead-free perovskite photosensitive layer 4, the organic flexible electron transport layer 5, the interface barrier layer 6 and the organic flexible electrode cathode 7, and finally forming the photomultiplier type fully flexible lead-free perovskite photosensitive diode, such as Figure 9h shown.

[0129] In a specific embodiment of the present invention, a PMMA or CYTOP organic silicone resin transparent encapsulation layer can be prepared by vacuum evaporation or solution spin coating.

[0130] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0131] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art can understand and implement other changes to the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0132] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A photomultiplier-type fully flexible lead-free perovskite photodiode, characterized in that: The invention comprises a flexible substrate (1), an organic flexible electrode anode (2), an organic flexible hole transport layer (3), a lead-free perovskite photosensitive layer (4), an organic flexible electron transport layer (5), an organic flexible electrode cathode (7) and an encapsulation layer (8), wherein: The flexible substrate (1), the organic flexible electrode anode (2), the organic flexible hole transport layer (3), the lead-free perovskite photosensitive layer (4), the organic flexible electron transport layer (5) and the organic flexible electrode cathode (7) are stacked in sequence from bottom to top; The encapsulation layer (8) is located on the upper surface of the organic flexible electrode cathode (7) and the upper surface of the organic flexible electrode anode (2), and is located on the side surfaces of the organic flexible hole transport layer (3), the lead-free perovskite photosensitive layer (4), the organic flexible electron transport layer (5) and the organic flexible electrode cathode (7); The organic flexible electrode cathode (7) fully covers the organic flexible electron transport layer (5) in the form of a thin film, or is distributed on the upper surface of the organic flexible electron transport layer (5) in the form of a uniform array of carbon nanotubes.

2. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 1, characterized in that: The flexible substrate (1) is any one of polyethylene terephthalate, polyethylene naphthalate, fluorinated polyimide, and polydimethylsiloxane; the organic flexible electrode anode (2) and the organic flexible electrode cathode (7) are any one of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate), polyaniline, and polypyrrole.

3. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 1, characterized in that: The lead-free perovskite photosensitive layer (4) is any one of ABX3 germanium-based perovskite, bismuth-based perovskite, and tin-based perovskite, wherein A is an organic cation, B is an inorganic metal cation, and X is a halogen ion.

4. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 1, characterized in that: The organic flexible hole transport layer (3) is any one of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate), poly(3-hexylthiophene), poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine], 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene, and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]; the organic flexible electron transport layer (5) is any one of [6,6]-phenyl-C71-butyric acid methyl ester, poly(9,9-dioctylfluorene-alternative-benzo[2,1,3]thiophene), polyetherimide, fullerene, and 8-hydroxyquinoline aluminum; wherein, The doping material of the organic flexible electron transport layer (5) is any one of molybdenum oxide, 4,4′-bis(diphenylamino)cyclohexane, and poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alternating-2,7-(9,9-dioctylfluorene)].

5. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 1, characterized in that: The thickness of the flexible substrate (1) is 50-500 μm, the thickness of the organic flexible electrode anode (2) is about 50-100 nm, the thickness of the organic flexible hole transport layer (3) is 30-300 nm, the thickness of the lead-free perovskite photosensitive layer (4) is 100-1000 nm, the thickness of the organic flexible electron transport layer (5) is 20-200 nm, and the thickness of the organic flexible electrode cathode (7) is 50-100 nm.

6. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 1, characterized in that: It also includes an interface barrier layer (6) located between the organic flexible electron transport layer (5) and the organic flexible electrode cathode (7).

7. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 6, characterized in that: The interface barrier layer (6) is any one of 4,4'-bis(diphenylamino)cyclohexane, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetra[N-(1-naphthyl)-phenyl]-9,9'-spirobifluorene, and 1,4-poly(p-phenyl).

8. The photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 6, characterized in that: The thickness of the interface barrier layer (6) is 5-20 nm.

9. A method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode, characterized in that: include: S1: Select a flexible substrate (1) and perform pre-treatment; S2: growing an organic flexible electrode anode (2) on the surface of the pre-treated flexible substrate (1); S3: growing an organic flexible hole transport layer (3) on the surface of the organic flexible electrode (2); S4: growing a lead-free perovskite photosensitive layer (4) on the surface of the organic flexible hole transport layer (3); S5: growing an organic flexible electron transport layer (5) on the surface of the lead-free perovskite photosensitive layer (4); S6: growing an organic flexible electrode cathode (7) on the surface of the organic flexible electron transport layer (5); S7: A layer of transparent medium is grown as an encapsulation layer (8) on the upper surface of the organic flexible electrode anode (2) and the organic flexible electrode cathode (7), and on the sides of the organic flexible hole transport layer (3), the lead-free perovskite photosensitive layer (4), the organic flexible electron transport layer (5) and the organic flexible electrode cathode (7), to finally form the photomultiplier type fully flexible lead-free perovskite photosensitive diode.

10. The method for preparing a photomultiplier-type fully flexible lead-free perovskite photodiode according to claim 9, characterized in that: Between S5 and S6, an interface barrier layer (6) is grown on the surface of the organic flexible electron transport layer (5).

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